Win32K.sys File Failure

How do you fix a win32K.sys file from giving you a blue screen after three hours of using the computer. I recently installed a Western Digital 30GB 7200RPM Hard drive and a 256 stick of PC2100 Kingston memory ( I previously had 512MB stick of PNY Optima 400Mhz DDRam all by itself) and I just can't get the dang thing stablized. I'm Running on Windows XP Home Edition SP2. Please help.